OK, I created a new library using the XML from my initial library and now things are getting really weird.
1) Even after adjusting the Music Folder path so that it's identical to my working library, only about half of the files can be located.
2) The unlocatable files have little exclamation marks next to them to indicate that they're not available. This is exactly the behavior I'm looking to replicate in my initial library (once I get the remapping figured out); why isn't that library behaving the same way?
3) When I try to play one of the unlocatable files in the new library, it asks me if I'd like to locate the file. When I click yes, it points me to exactly where the file is. The "path" shown for each is also correct, so I'm not sure why it can't locate them. But if I can correct this issue, I think this will get me what I need.
Also, probably related to point #2: when I try to play a file in my initial library, it just tells me that it can't be found. There's no option to locate it.
4) Edit: Nevermind, I was looking at the wrong place.